Lapping-machine



C. G. OLSON.

LAPPING MACHINE.

APPLICATION FILED MAY 24, 1919.

1 ,360,435 Patented Nov. 30, 1920.

4 SHEETS-SHEET 1.

' @rZ Q. 0Z607g c. a. OLSON. LAPPING MAC-HINE.

APPLICATION FILED MAY 24, 1919.

0 2. 92 IT n 3 Wm W. d4 w n m P @rZ & (9560 1 .C. G. OLSON.

LAPPING MACHlNE.

APPLICATION FILED MAY 24. 1919.

m Am w w m r g: a

G. G. OLSON.

LAPPING MACHINE.

APPLICATION FILED MAY 24, 1919. 1,360,435.

4 SHEETS-SHEET 4.

Patented Nov. 30, 1920.

UNITED STATES PATENT OFFICE.

ARI, G OLSON OF CHICAGO, ILLINOIS, ASSIGNOR T ILLINOIS TOOL WORKS, OF

CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS- I I LAPIING-MACHINE.

Application filed May 24,

To all whom it may concern:

Be it known that I, CARL Gr. OLsoN, a citizen'of the United States, residing at Chicommonly known as gear cutting hobs. The

general object is .to provide a machine capable of producing a hob having the same qualities as 'a ground hob. Another object is to provide a machine capable of lapping all of the hob teeth at the same time, thus greatly reducing the amount of time required to finish the work. Another object is to provide a construction capable of producing v substantially perfect uniformity of the hob .teeth. Another object is to render the machine largely automatic in its nature, thus'saving time and labor on the part of the attendant. Contributory objects, by which these main objects are carried out, will become apparent as the description proceeds.

I accomplish my objects by the mechanism illustrated in the accompanyingdrawings, in which- Figure 1 is an end elevation of the machine looking toward the left in Fig. 2.

Fig.2 is a side elevation of the machine, chiefly in section on the line 22, Fig. 1.

- Fig. 3 is a sectional elevation on the line 33, Fig. 1.

Fig. 4 is a side view of one of the lap holders and associated parts. Fig. 5 is a detail illustrating the manner by which the cam plate may be utilized to hold the lap out of contact with the hob.

Fig. 6 is a detail view illustrating the manner in which the laps and other holders are arranged around the hob and also illustrating the oscillatory movement made by the hob during the active operation of the machine.

out the several views.

In the form of machine shown in the drawings" for illustrating the principle of the in Specification of Letters Patent.

Patented Nov. 30, 1920. 191.9. Serial No. 299,589.

vention the main shaft is journaled in a bearing 2 and a sleeve 3, said bearing being supported upon the column 4 rising'from the base plate 5 of the machine; Thesleeve 3 1s journaled in a bearing 6 which is sup ported upon a column 7 also rising from said base plate; The work 10 which is shown in the form of a hob is rigidly fastened to shaft'l in any suitable manner. Said shaft may, therefore, be regarded as the work holder.

The main shaft or work holder is designed to oscillate through a comparatively narrow angle for example, an angle considerably narrower than the one subtended by a singletooth of the hob. This oscillatory movement of the work holding shaft is produced by means of an index plate, best shown in Figs. 2 and 3. This plate has a sleeve 13 which encircles the shaft, and is prevented from moving lengthwise of the shaft by being confined between the bearings 2 and 6, previously mentioned.

The plate and sleeve are splined to the shaft by means of a feather 14, the keyway 15 in the shaft being considerably elongated in order to permit the shaft to shift longitudinally, at the same time that it rocks. The index plate 12 is oscillated by means of a rocking member 17 which encircles and rests upon sleeve 13 and has an arm 18'carrying a detent 19, the lowerend of which is adapted to enter the various notches 20 formed in the,periphery of the plate. Said detent is normally urged toward the plate by means of a spring 21. The rocking member 17 has an arm 23, the lower end of which is vertically slotted or bifurcated to receive an eccentric 24 formed upon shaft 25. Said shaft is journaled in a bearing 26 formed in the column 4, and is driven by a pulley 27 or other suitable power devlce, with the result when theshaft 25 is rotated, it will cause the member 17 to oscillate, and the latter, acting through detent- 19, will cause the index plate 12 and shaft 1 to oscillate.

Rising from and preferably integral with the bearingf6 is a bracket 30. Adjacent to it on the s de opposite to the index plate 12 is a face plate 31 which is here shown to be integral With sleeve 3 and is prevented from rotating by means of a pin 32 (best shown in Figs. 2 and 5). This pin passes through the face plate into the bracket 30 and is thus prevented from rotating. Rigidly fastened to the face plate 31 by nuts 34 or otherwise,

are posts 35 equal in number to the hob teeth. Each of these posts forms a pivotal support for an arm 36 which, in the present case, is yoke shaped, and is provided with two branches 37, 37. As shown in detail in Fig. 4, these branches carry conically pointed pins 38, 38 which form centers for supporting the lap holders 40. The lap holders are also U-shaped in the present design and sup port the laps 41 which are held in position by tap screws 42, 42 or other appropriate devices. In order to prevent the lap'holders from rotating too far about their center pins 38 they are provided with a stop pin 44 which screws into one side of the lap holder and passes out through an elongated slot 45.

The laps are of lead or other soft metal or alloy and are accurately formed, their active surfaces being configurated to accurately fit properly formed. hob teeth. The

the work holder.

laps are by preference in the form of flat blocks of a length one or two notches longer than the hob which is to be treated. The purpose of this is to enable the laps to engage both sides of all of the hob teeth no matter which set or row of teeth are being acted upon.

' The laps are pressed toward the work by means of springs 48 whichin the preferred construction take several turns; around the respective posts 35, one end being brought out so as to back up the arm 36 and the other end being brought' out so as to engage the respective pins 49 projecting laterally from the cam ring 50. Said ring encircles the face plate 3 and makes sliding contact with the periphery thereof. It is held in position on the plate by means of a flat ring 51. Its angular position is governed by a handle 52.having a base 53 which is fastened to said ring bv means of screw 54, or otherwise. The bracket 30, previously mentioned, has a segmental plate 57 at-the upper end, having a row of apertures 58, centered at the axis of shaft 1.

-A pin 59 carried by-the handle 52 is adapted to enter into .one of the apertures 58 and hold the cam ring 50 in the desired angular position. Said cam ring has a cam 60 for each of the arms 36. These cams are adapted to cooperate with tails 61, extending from each of the arms 36 in such manner that when the cam plate is angularly shifted toward the left, Fig. 5, the cams will engage the parts 61 and rotate the arms 36 in such direction as to retract the laps from the hob, as shown in Fig. 5. When the laps and their supporting parts are thus held in retracted position, the hobs may be readily removed from or positioned upon When the cam plate is shifted angularly toward the right, the cams will free the tails 61 and permit the springs configuration.

strike the end of the into the proper aperture 58, whereupon the machine may be started.

- The pulley 27, in rotating, causes the eccentric 24 to rock the element 17 about the main shaft 1 and this, acting through the index plate 12, causes the shaft to oscillate and oscillate the hob. As the hob-teeth are arranged helically it is evident that the rotary movement of the hob, even though confined to a small angle, produces a movement of the hob in an axial direction. This is arranged for, however, for shaft 1 which constitutes the work holder is slidable longitudinally in its bearings and in the sleeve 13 of the index plate. Hobs, of course, have relieved teeth-that is, their outer surfaces are not concentric with the axis of the hob, but are eccentric. The resultis that the oscillatory movement of the hob produces a vibratory movement of the arms 36 about their pivot posts 35. The springs'48, however, keep the laps at all times pressed against the surface' of the hob teeth, thereby producinga'rubbing action, thus rubbing down or lapping the surfaces of the hob teeth to bring'them to perfect and accurate Although the arms 36 vibrate to compensate for the relief of the hob teeth, there is produced, in addition, an oscillation of the laps about their pivot pins 38 as illustrated in Fig. 7. This enables thev machine to accommodate hobs of different sizes and hobs having different ratios of relief. The axial point of the lap holder is so located with respect to the teeth of the lap that the pressure of the lap upon the hob, teeth will be substantially uniform at all points of the surface of the hob teeth. I have found that it desirable, in order to secure this effect, to so construct the parts that the axis of oscillation of the lap holderz. 6., the center line of the pins 38, will pass through what may be regarded as the pitch line of the lap teeth, half way between the front and backof the lap; in other words, the axis of oscillation is centered with respect to the thickness of the lap and lies substantially in the pitch circle of the lap teeth. Although the lap holders are thus free to oscillate about their center pins 38, said holders will not swing far out of position when the arms 36 are in retracted position (see Fig. -5). The stop pins 44 will slots 45 formed in one of the branches 3? of arms 36;. in fact, the

construction is such that the laps will have free play so far as necessary to maintain good contact with thehob teeth, but will never swing so far away from acting posi tion that they will not automatically resume acting position when the arms 36 cause them to approach the hob. After the laps have been in contact with one set of teeth for a short time, theoperator stops the machine,

rotatesthe cam'ring 50 so as to retract the I teeth.- The machine is .then started up again and operated for another. short interval, after which the operator goes through the same performance and brings still another row of teeth into contact with the laps. This performance may be repeated as many times as desired, but in any event the result will be to produce practically perfect accuracy in the teeth. It will be evident that if a given hob tooth has a particularly high point it would ultimately affect the lap in contact with it in case the entire lapping operation were completed without angularly shifting the hob;but by thus bringing the laps successively into contact with diiferent rows of teeth, the laps will wear uniformly 'and will produce uniformity in the hob teeth. It will be understood, of course, that the hobs are fairly accurate before they are mg surfaces are supplied with a lubricant with which is mixed powdered carborundum' or other abrasive. I have found by experience that the carborundum particles apparently become embedded in the acting surface of the laps and on this account and on account of the presence of the lubricant the wear upon the laps is much less than might be expected. Hence it is possible to configurate the laps very accurately to the size which the finished hob teeth must conform to, and the laps last much longer before becoming excessively worn than might beanticipated.

One of the great advantages of my machine over an ordinary hob grinding ma-- chine is that it is capable of acting upon all of the hob teeth simultaneously instead ing machine.

holder adapte .adapted to engage the teeth of the hob,

of one at a time as with the ordinary grind- Thus the time required for finishing the hob is greatly reduced. This, taken in connection with the great accuracy with which the hob teeth are formed,renders the machine of great value in connection with the production of hobs and similar gear cutters. p Having thus described my invention what I claim as new and desire to secure by Let ters Patent, is: i

1. A machine for lapping hobs havin a work holder for supporting the hob, a p urality of laps encircling the hob, and means for causing relative angular movement between the laps and hob, the work holder and the laps being adapted to move relatively in a direction parallel to the axis of the hob, the laps being adapted to em gage opposite sides of the hob teethwhereby the lead of the hob teeth causes relative reciprocation in a direction parallel to the axis of the hob.

2. A lappin machine having a. work to support a hob, a lap means for causing relative angular movement between the lap and the hob, the lap and thehob being relatively movable in a direction parallel to the axis of the hob, and a lap holder pivotally mounted so as to accommodate the eccentricity or relief ofthe hob teeth.

3. A lapping machine having a work holder adapted to support a hob, a lap adapted to engage the teeth of the hob, means for causing relative angular movement between the lap and the hob, the lap and the hob being relatively movable in a direction parallel to the axis ofthe hob, and means for yieldingly pressing the lap against the hob teeth.

4.. A lapping machine having a work holder which isoscillatable about a fixed axis, means for oscillating it rapidly about its axis, a plurality of laps arranged approximately radially about the axis of the work holder, a holder for each of the laps, and an arm for each of the lap holders, the lap holders being pivotally mounted in their respective arms, and means pivotally supporting said arms.

5. A lapping machine having a work holder which is both oscillatable and axially shiftable, a plurality of laps adapted to rub the work. and a holder for each of the laps, and an arm for each of the lap holders, the lap holders being pivotally mounted in their respective arms, and means for pivotally supporting said arms.

6. A. lapping machine having a shaft adapted to support the work, means for oscillating said shaft about its axis, laps arranged approximately radial'l about the axis of the shaft, lap holders or said laps,

arms in which said, lap holders are pivotally supported, posts on which said arms are pivotally supported, and springs for forcing'the laps toward the work.

7. A lapping machine having a shaft adapted to support a hob, said shaft being longitudinally shiftable, means for oscillating said shaft about its axis, laps arranged approximately radially about the shaft, said laps having teeth adapted to engage the hob teeth, lap holders for said laps,

teeth, a pivotally supported arm adapted to support said lap, a cam adapted to hold said arm in non-acting position, and means for positioning said cam.

9. A lapping machine having a work holder adapted to support milling cutters,

hobs, andsimilar substantially cylindrical objects, a plurality of laps arranged radially about the axis-of thework holder, lap holders, arms for pivotally supporting said lap holders, said arms being adapted to move the laps toward and from the Work, and means for limiting the amount of rotation of the lap holders relatively to said arms.

10. A lapping machine having an os-- cillating shaft adapted to support millin cutters and the like, a face plate arranged at right angles to the shaft, concentric therewith, posts extending from the face plate parallel to the shaft, arms pivoted on said posts, and laps pivotally mounted insaid arms in position to engage the teeth of the work.

11. A lapping machine having an oscil- 'lating shaft adapted to support milling cutters and the like, a face plate arrange at right angles to the shaft,concentric therewith, posts extending from the face plate parallel to the shaft, arms pivoted on said posts, laps pivotally mounted in said arms in position to engage the teeth of the work,

and springs anchored at one end to theface plate and the other end to said arms for yieldingly holding the laps in engagement with the work.

12. A lapping machine having an oscillating shaft, adapted to support hobs and the like, 'a face plate arranged at right angles with the shaft concentric therewith, posts extending from the face '(plate parallel to the shaft, arms pivote on said posts, laps pivotally mounted on the said arm in position to engage the teeth of the work, said shaft beinglongitudinally shiftable to accommodate the lead'of the hob teeth, and springs adapted to urge the laps toward the work;

, 13. A lapping machine having a work holder adapted to support substantially cylindrical cutters having relieved teeth, laps adapted to act upon the teeth of the laps are pivotally mounted to enable them to automatically maintain surface contact vwith the teeth of the work, and means for ber for the hob, means for producing relative reciprocatory movement between the hob and the laps in an are centered at the axis .of the hob, and pivots for supporting the lap in the supporting member, said lap having teeth mating with the hob teeth for making surface contact'therewith, and the axis ofthe pivots passing substantially through the pitch circle of the lap teeth.

15. A lapping machine having a work holder, a rotatable shaft for actuating the work holder, an index plate, actuating means adapted to engage said index plate for oscillating it, said plate being adapted to oscillate the shaft and being angularly adjustable with respect to said actuating means, a lap and means for holding said lap in contact with the work.

16. A lapping machine having a work holder adapted to support a hob, a rotatable shaft for actuating the work holder, an index plate splined to said shaft, actuating means adapted to oscillate said index plate, said plate being angularly adjustable relatively to said actuating means, a lap adapted to engage the teeth of the work, and supporting means for holding said lap in contact with the hob teeth, said supporting means being adapted to hold the lap against movement in a direction parallel tothe shaft and adapted to permit the lap to assume different positions in a planetransverse to the axis of the hob to enable it-to maintain contact with the relieved hob teeth.

17. A lapping machine having a shaft adapted to oscillate about its axis, said shaft being adapted to support a hob coaxially, an index plate splined to said shaft, an eccentric located at a point remote from the axis of the shaft, means for rotating said eccentric, a connecting member actuated by said eccentric and adapted to oscillate the index plate about its axis to thereby oscillate the shaft, said index plate'being angularly ad .work, supporting members in which said justable with respect to said connecting member, a lap, and means for holding said eccentric and adapted to oscillate the index plate about its axis to thereby oscillaterthe shaft, said index plate being angularly ad-' justable with respect to said connectin member, and a lap adapted to engage an rub the hob teeth, said lap being held; against movement parallel to the shaft and being adapted to move relatively to its sup port for enabling it to maintain surface contact with the teeth of the hob.

19. A lapping machine having a workv holder, a shaft adapted to actuate the work" and supporting members for moving the holder, an index plate adapted to oscillate said shaft, said plate having a hub, an actuf ating member journaled on said hub and adapted to engage said index plate at chosen points on its circumference,- means for oscillating said actuating member, a lap, and means adjacent to the work holder for holding the lap in contact with the'work.

20. A lapping machine having a work holder, a shaft adapted to actuate the work holder, an index plate adapted to oscillate a said shaft, an actuating member adapted to engage said index plate at different points on its circumference, an eccentric, remote from the shaft andadapted to engage said actuating member for oscillating the index plate, means for rotating said eccentric, a

lap, and means for holding the lap in contact with the work.

21. A lapping machine having a work holder, ashaft adapted ,to actuate the work holder, an 'index'plateadapted to oscillate said shaft, said plate having a hub,'an actuating member ournaled on said hub and adaptedto engage said index plate at chosen points on itscircumference, an eccentric located at a distance from the shaft for oscil-" .lating-said actuating member, a lap, and

means adjacent to the work holder for bold ingthe lap in contact with the work.

22A lapping machine having a work holder adapted to support cutters having relieved teeth, laps for rubbing the teeth,

laps practically radially with respect to the cutters, saidlaps being pivotally mounted in said so portingmembers and having a free and in ependentmotion in the supporting members whereby the laps are able to automatically maintain surface contact with the teeth of'the work. 7 I

, In,v witness whereof, I have hereunto subscribed my name.

1 CARL G. OLSON 

